Tires that can run on long after their air is gone have always seemed like a good safety idea. Why risk your life changing a blowout at the edge of a busy freeway? Why become an immobilized victim in a dangerous neighborhood just because a tire leaked?
Run-flat tires look like a can't-miss safety solution. But for the mass market of consumers, run-flat tires continue to be a safety solution searching for a problem.
Existing tires are too good at what they do, and too cheap, to make room for the new technology. Some new factor has to push the more costly run-flat systems, because a market pull just isn't there.
Flats were once a regular part of driving. Now, they're a rare occurrence for most drivers. Even when they happen, many are mundane slow-leak flats discovered in driveways and parking lots. Federal safety agencies don't track flat-tire statistics. Even the Tire Industry Safety Council doesn't do a count.
The 42-million-member American Automobile Association reported nearly 3.3 million flat-tire assistance calls in 1998, just 11 percent of all service calls for the insurer. Nearly 215 million replacement tires were sold in 1998, according to Modern Tire Dealer, but that number includes all replacements, not just blowouts.
But if consumers aren't clamoring for run-flats, the safety technology may just catch on for a different reason: Automakers want run-flat capability. It gives them a chance to shave pounds off a vehicle's weight and open up cargo space by eliminating the spare tire and jack. It also gives them a new marketing angle for an aging baby-boom generation with an increasing focus on safety.
'All the tire companies are working aggressively with the engineering departments of the auto manufacturers,' says Saul Ludwig, a tire industry analyst at Cleveland-based McDonald & Co.
Michelin North America Inc., Continental General Tire Inc. and Goodyear Tire & Rubber Co. are the North American leaders, with three different forms of run-flat technology.
Goodyear's EMT tire technology is rolling on Chevrolet Corvettes and Plymouth Prowlers. But no manufacturer has ventured to specify run-flat tires as original equipment on a new, high-volume production vehicle. Until that happens, setting an industry standard for the tires, the technology is likely to remain in modest, specialized applications.
'Twenty years from now, it could be the standard for the industry,' Ludwig says. 'The key is to have one way chosen.'
When a run-flat system is mounted on a car, it requires a tire pressure monitoring system to alert the driver to a tire failure, as well.
So far, such systems have focused on two different technologies. In one, a battery-operated pressure sensor is strapped or valve-mounted to the inside of the wheel. It broadcasts a radio signal from the tire to a receiver in the car.
The other system uses either the antilock brakes or a special tire sidewall sensor to 'count' wheel revolutions. A tire going flat will shrink in size, meaning more rpms over a given distance, or show more variation in how far the sidewall deflects in maneuvering. So the cost of the new sensor system also must be incorporated into the run-flat equation. And the system's reliability becomes a new question for liability-conscious manufacturers.
Then there's the tire dealer who must adapt to a run-flat system.
'This completely changes the picture for the dealer,' says independent tire engineering specialist Jacques Bajer, who in the 1960s helped introduce the radial tire to the North American market while working at Ford Motor Co. 'The existing tire mounting machine must at least be modified. Is it something the replacement market, the independent dealers, who are already starving to death, are prepared to do?'
But the bigger obstacle, Bajer says, is that 'the public has a perception that tires are so good, so reliable, that they ignore them.'
For now, at least, the safety advantages that are offered by run-flat technology haven't struck a chord with consumers.
Tim Moran is a free-lance reporter based in Grosse Pointe Park, Mich.